The present invention refers to a device for axial adjustment of a rotatable body which is mounted in a bearing.
More specifically, the present invention provides a bearing assembly rotatably supporting a shaft journal having a gear wheel at one end in a housing in a manner so that it may be easily adjusted to mesh with the pinion of gearing.
The invention is intended to be used primarily for supporting bodies, the axial position of which it is desirable to be able to adjust very accurately. As an example can be mentioned the supporting of a pinion gear wheel, the position of which must be adjustable in order to bring about an accurate gear contact between the pinion and the crown wheel of a gearing.
It is earlier known to use spacer washers between the end surfaces of a pinion bearing ring and a radial shoulder at a bearing seat in order to bring about axial adjustment of a pinion gear wheel. The adjustment procedure when using this method is however troublesome and timewasting and it requires qualified work. It is further known to mount the pinion bearing in surrounding sleeves, which have an external cylindrical portion and a portion provided with screw threads, the sleeves thereby being arranged axially displaceable in a cylindrical seat in the gear housing, the screw threads engaging in corresponding screw threads provided in the gear housing. The sleeves will be displaced axially when turned, whereby also the bearing and the pinion gear wheel will be displaced in relation to the gear housing, which means that the adjustment of the pinion can be brought about by turning of the sleeves.
The difficulties with such a device are the inevitable form defects which will occur at the manufacture of the sleeves, e.g. tolerances, excentricity, out-of-roundness and angular defects and dimension changes at operation in the form of contact deformations, flexing and thermal expansion. These factors will influence the gear contact. This device will furthermore require large space and it is heavy and requires considerable costs. The negative factors have together resulted in that the device has been used only very little in practice.
It is also known to provide the envelope surface of a bearing ring with threads along its whole extension and to provide a bearing seat with corresponding threads, thereby making it possible to adjust the axial position of the bearing in the seat by turning the threaded bearing ring. The threading, however, makes it difficult to maintain an accurate angular and centric position of the bearing, since it is difficult to machine the thread exactly concentrically and coaxially with the seat and the raceways, respectively, and to give the threads proper tolerances.
The purpose of the present invention is to provide a bearing arrangement with a bearing, which in operation when arranged on a rotatable body will make possible an accurate adjustment of the body which is maintained during operation.
This is according to the invention achieved thereby that the bearing arrangement has been given the characteristics defined in the attached claims.